Luminescence dynamics of CdS-doped glasses were measured using up-conversion technique, and they were compared with transmission dynamics. An analysis of the decay curves of luminescence and transmission dynamics has been performed using a multi-exponential fit.Although slower decay component is large in transmission dynamics, it is negligibly small in luminescence dynamics. This difference is observed in all samples investigated, and this may be caused by the difference in relaxation paths of electrons and holes in CdS nanocrystals. Effect of induced absorption on transmission dynamics was examined.